In some self-propelled snow removers, a snow-removing implement is attached to a machine body so as to be capable of lifting, lowering, and rolling, and a travel unit is provided to the machine body. The snow-removing implement is composed of an auger, for example. In a snow remover provided with an auger, a system is adopted whereby the height of the auger is varied according to snow removal circumstances. Such an auger-type snow remover is described in Japanese Patent Laid-Open Publication No. 10-219643.
The auger-type snow remover described in the 10-219643 publication has a travel unit; a machine body to which the travel unit is provided; a snow-removing implement attached to the front of the machine body so as to be capable of lifting, lowering, and rolling; and left and right operating handles and an operating unit attached to the rear of the machine body. An operator can steer the left and right operating handles and operate the operating unit while walking along behind the snow remover.
The operating unit of the auger-type snow remover (self-propelled snow remover) described in the 10-219643 publication will be described with reference to FIG. 28 hereof. FIG. 28 is a top plan view of the operating unit in the conventional self-propelled snow remover.
The operating unit 300 in the conventional self-propelled snow remover is elongated to the left and right and is provided with a travel shift lever 301 disposed in the center position, a four-way operating lever 302 disposed on the right side of the shift lever 301, a slide switch 303 disposed at the top of the four-way operating lever 302, a rolling auto-switch lever 304 disposed on the left side of the shift lever 301, and a manual switching lever 305 disposed immediately to the right of the rolling auto-switch lever 304.
When the four-way operating lever 302 is swung forward or backward, the snow-removing implement is lifted or lowered. When the four-way operating lever 302 is swung to the left or right, the travel units travel and make a turn. When the slide switch 303 is slid to the left or right, the snow-removing implement rolls regardless of the switching position of the rolling auto-switch lever 304. When the operator lets go of the slide switch 303, the snow-removing implement automatically returns to the horizontal state.
When the rolling auto-switch lever 304 is moved into the automatic position, a control unit controls the snow-removing implement so that a horizontal state is constantly maintained. When the rolling auto-switch lever 304 is moved into the manual position, the snow-removing implement can be rolled by swinging the manual switching lever 305.
During snow removal, the operator raises, lowers, and rolls the snow-removing implement according to the terrain being cleared. The snow-removing implement can be raised, lowered, and rolled by operating the four-way operating lever 302 and the slide switch 303 with the right hand.
However, the snow-removing implement automatically returns to the horizontal state when the operator removes his right hand from the slide switch 303. The operator cannot let go of the slide switch 303 when he wishes to stop the snow-removing implement in an arbitrary rolling position. Therefore, when the operator wishes to stop the snow-removing implement in an arbitrary rolling position, he uses his left hand to swing the manual switching lever 305 disposed on the left side of the operating unit 300. Since lifting/lowering and rolling of the snow-removing implement are performed with different hands, operation is complicated and inconvenient. The ability to enhance the ease of operation is limited in this case. In contrast, it is conceivable that lifting/lowering and rolling of the snow-removing implement could both be performed by swinging the four-way operating lever 302 forward, backward, left, and right using one hand.
It is sometimes preferable to return the orientation of the snow-removing implement to a predetermined initial position with one operation during snow removal. For example, the operator often turns the snow remover according to the snow removal situation. Because the snow removal operation is under way, the auger and auger housing are lowered to a point near the road surface. When the snow remover is turned in this state, accumulated snow interferes with turning depending on the state of snow accumulated around the snow remover. The snow-removing implement must therefore be raised each time the operator turns the snow remover. Once the turn is completed, the snow-removing implement is again lowered to a point near the road surface and aligned with the angle of the road surface. Due to the inconvenience of this type of operation, greater efficiency is obtained by returning the snow-removing implement to a reference position using a single operation, and then performing fine adjustment using this reference position as a reference.
Even when raising/lowering and rolling of the snow-removing implement are both performed by swinging the four-way operating lever 302 forward, backward, left, and right as described above, rapidly returning the snow-removing unit to a reference position is preferred.
There is therefore a need for a technique whereby the orientation of the snow-removing implement can easily be manipulated, and the operation for returning the snow-removing implement to a reference position can be rapidly performed.